tvl-depot/users/wpcarro/emacs/pkgs/struct/struct.el
William Carroll 15c9ff4902 feat(wpcarro/emacs): Package al, list, set, struct
Originally I set-out to package `al.el`, but as I started traversing the
dependencies, I needed to package increasingly more packages. I refactored some
of these to prune their dependencies to slay this hydra before it turned into a
never-ending project. I have mixed feelings about this.

I also introduced `ert` and unit tests into my Elisp packaging, so it'll be nice
to have build-time tests that run when Emacs updates land in depot.

Change-Id: I2756dc60888b80255a495e08ae61bd547e6b3db2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5998
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI
2022-07-29 03:35:19 +00:00

68 lines
2.1 KiB
EmacsLisp

;;; struct.el --- Helpers for working with structs -*- lexical-binding: t -*-
;; Author: William Carroll <wpcarro@gmail.com>
;; Version: 0.0.1
;; Package-Requires: ((emacs "24.3"))
;;; Commentary:
;; Provides new macros for working with structs. Also provides adapter
;; interfaces to existing struct macros, that should have more intuitive
;; interfaces.
;;
;; Sometimes `setf' just isn't enough.
;;; Code:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Dependencies
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 's)
(require 'dash)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Library
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defmacro struct-update (type field f xs)
"Apply F to FIELD in XS, which is a struct of TYPE.
This is immutable."
(let ((copier (->> type
symbol-name
(s-prepend "copy-")
intern))
(accessor (->> field
symbol-name
(s-prepend (s-concat (symbol-name type) "-"))
intern)))
`(let ((copy (,copier ,xs)))
(setf (,accessor copy) (funcall ,f (,accessor copy)))
copy)))
(defmacro struct-set (type field x xs)
"Immutably set FIELD in XS (struct TYPE) to X."
(let ((copier (->> type
symbol-name
(s-prepend "copy-")
intern))
(accessor (->> field
symbol-name
(s-prepend (s-concat (symbol-name type) "-"))
intern)))
`(let ((copy (,copier ,xs)))
(setf (,accessor copy) ,x)
copy)))
(defmacro struct-set! (type field x xs)
"Set FIELD in XS (struct TYPE) to X mutably.
This is an adapter interface to `setf'."
(let ((accessor (->> field
symbol-name
(s-prepend (s-concat (symbol-name type) "-"))
intern)))
`(progn
(setf (,accessor ,xs) ,x)
,xs)))
(provide 'struct)
;;; struct.el ends here